Ribbon reversing mechanism for writing machines



Nov. 15, 1949 J. M. STOLZ 2,487,834

RIBBON REVERSING MECHANISM FOR WRITING MACHINES Filed March 7, 1946Patented Nov. 15, 1949 RIBBON REVERSING MECHANISM FOR WRITING MACHINESJames Marshall Stolz, Los Angeles, Calif.

Application 'M archfl, 1946, Serial No. '652,752

2 Claims.

(Granted under the act of March 3, 1883, as,

means is provided for the automatic reversal of the inked ribbon when ithas become completely wound upon one spool, and manual reversal isnecessary. Several disadvantages arise from this condition. Frequently,an operator will reverse the ribbon well before the proper time, andthis results in nonuse of a substantial portion thereof. On the otherhand, an operator in some cases may fail to note that reversal isnecessary; the machine then types on one part of the ribbon only,reducing the clarity of the printed matter and perhaps wearing a hole inthe ribbon. In

extreme cases, breakage of the ribbon occurs.

The principal object of this invention is to provide a novel means forautomatically reversing the ribbon in a typewriting machine of thenature indicated so as to eliminate the aforementioned difliculties.

Other objects will be apparent from a reading of the followingspecification and claims.

The single drawing is a front View, partly broken away, of the ribbonreversing mechanism of my invention.

Referring to the drawing, the typing and ribbon winding elementsinthemselves substantially conventional-may be seen to include a typewheelI0 having numerals, letters and other indicia on the periphery thereof,the typewheel being adapted to be driven by a power source (not shown),two ribbon spools II and I2, provided with toothed driving wheels, as II and I2, respectively, and an arm I5 having two teeth I5 and I5", thefirst being adapted to cooperate with wheel I I' and the second withtoothed wheel I2. the same power source which drives print wheel I0; itsaction is to engage the toothed wheels II and I2 and to wind the ribbon2U first in one direction and then in the other.

In a construction of this nature, difilculty is 50 encountered with anyarrangement which depends for shifting arm I5 upon the strain whichgradually builds up in the ribbon when the ribbon is run completely offone spool since the first action is to move arm I5 out of engagementwith 5 amended April 30, 1928; 370 O. G. 757) Arm I5 is driven throughan eccentric by 45 For the true scope of the invention, reference itscooperating ratchet wheel and thus prevent further advance of theribbon.

Briefly, my invention provides means for preventing. any movement of armI5 until enough strain has been accumulated to. snap the arm quicklytoits secondoperative position, namely (according to the drawing), inengagement with ratchet wheel I2.

According to my invention, the ribbon 20 is threaded through theapparatus in substantially conventional manner, as from spool II,through guides 2I, 22, and 23, and to spool I2. Guide 22, it will beunderstood, is furnished with an opening 22' through which a hammer (notshown) may cooperate with typewheel I0 to cause a character to beprinted.

Assuming that the parts are in the conditions shown in the drawing, theribbon being almost completely wound upon spool II, the eyelet 30, whichis located adjacent the end of ribbon 20, will catch in the guide 23. Asratchet wheel II continues to step, lever 3 I pivoted at 32, will moveunder the urging of eyelet 3!! and abut against lever 33, pivoted at 34.Movement of lever 3|, therefore, first increases the tension on springand then, acting through lever 33, moves pin 36, normally bearingagainst plate 31 above the corner 39 of said plate. It is this pin whichprevents premature movement of arm I5. The parts are so calculated thatby the time pin 36 clears plate 31 spring 35 is under sufficient tensionto move arm I5 rapidly into engagement with ratchet wheel I2,notwithstanding the restraining influence of spring 40.

At the same time, pin 45, urged by spring 46, shown in the drawing asbeneath the lower edge of plate 31, moves into a position substantiallylike that previously occupied by pin 36 but against the opposite side ofplate 31.

The operations are then repeated except that ratchet wheel I2 is rotatedby tooth I5 of arm I5 and the ribbon wound upon spool I2.

The foregoing description is in specific terms, and many modificationswill suggest themselves.

should be had to the appended claims.

I claim:

1. In a ribbon reversing mechanism for a writing machine, including tworibbon spools and a ribbon having elements adjacent the ends thereof ofsubstantially greater thickness than the ribbon, two ratchet wheels eachadapted to drive one of said spools, a ratchet adapted to drive saidwheels alternately, and means for controlling 5 said ratchet including apivoted lever having a ribbon guide thereon adapted to be engaged by oneof said thickened elements, continued movement of the ribbon after suchengagement resulting in movement of said lever upon its pivot, a springassociated with said lever and with said ratchet, said spring beingadapted to have its tension increased by movement of said lever, and asecond lever adapted when in one position to bear against said ratchet,said second lever being adapted to be moved out of engagement with saidratchet by said first lever after a predetermined movement of said firstlever.

2. In a ribbon reversing mechanism for a writing machine, a first ribbonspool, a first ratchet wheel for driving the same, a second ribbonspool, a second ratchet wheel for driving the same, a ratchet having onenormal position in engagement with the first ratchet wheel and a secondnormal position in engagement with the second ratchet wheel, and meansfor shifting said ratchet from each of said normal positions to theother including a first lever and a second lever, a first springconnecting said first lever and said ratchet, a second spring connectingsaid second lever and said ratchet, said levers being adapted to be putunder strain by means adjacent the end of a ribbon, said springs beingadapted to have their tension increased by the lever associatedtherewith as the same is put under strain, a first member and a secondmember, each having two normal positions and each

